KINGSTON — For the first time, harvesting of geoduck and other shellfish has been approved just outside Appletree Cove.

The state Department of Health recently reclassified 162 acres of commercial shellfish growing area from Prohibited to Approved. Soon, the Suquamish Tribe and Tulalip Tribes will survey the area for biomass — random sampling for geoduck weight and density in the survey area, between minus 18 and minus 70 feet in depth. The area reclassified is within the two tribes’ Usual and Accustomed Area for shellfish harvesting.

Viviane Barry, Suquamish Tribe shellfish program manager, said it will take time before any harvesting is done. First, pre-harvest surveys will be conducted by the tribes or state Department of Fish and Wildlife staff to calculate the estimated poundage of the newly opened area. That information will update the total allowable catch for the region in which the tract is located, Barry said.

The state departments of Health, Fish and Wildlife, and Ecology, and the tribes co-manage the harvesting of shellfish.

“This [approved status] potentially will add a few acres to that track, on the north side of the closure radius,” she said. “We haven’t calculated how many acres of geoduck bed the new classification will open.”

Geoduck tracts are subtidal unit areas where geoduck resource is present, Barry said. Co-managers from tribes and state agencies determine what constitutes a tract based on a variety of logistic, economic, legal and biological considerations. Tracts are usually set between depths of -18 to -70 feet.

Each harvest area is also sustainably managed. Once the biomass (weight and density of a geoduck tract) is calculated, a tract is usually only harvested up to 65 percent of the pre-harvest biomass, and then allowed to recover for a few years, Barry said.

Of the tens of millions of pounds in a region, that number is divided into an annual harvestable amount, of which half goes to the tribes and half to the state, Barry said. The harvest rate was adopted in 2000 using an age-structured equilibrium model of the geoduck population. Based on life cycles and management practices, 2.7 percent is the harvest rate used to determine the annual total allowable catch.

Barry said it is important to note that this rate is applied to geoduck biomass from surveyed tracts and not to the virgin biomass. Geoducks are present outside surveyed tracts from intertidal areas to -330 feet or deeper. The sum of all geoduck tracts in areas approved for shellfish harvest represents only a sliver of the virgin biomass.

“We’re always learning,” Barry said. “This [2.7 percent] potentially could change in the future.”

In 2013, Barry said Suquamish will harvest approximately 480,000 pounds of geoduck clams from various areas in Puget Sound. The Tribe harvests geoduck for subsistence, ceremonies and commerce. Suquamish Seafood Enterprise (SSE) is in charge of harvesting and selling product to domestic and international markets. SSE hires Suquamish tribal members who are trained in surface air supply diving to harvest the Tribe’s share of geoduck.

Barry is enthusiastic that the water quality has improved so that more tracts can be opened.

“Not only are we managing what is currently available, but we always try and work with all agencies to reclassify areas that are un-harvestable,” Barry said.

Shellfish growing and harvesting in Puget Sound is a challenge, Barry said.

“Suquamish mostly lives in an urban area,” Barry said. “It’s a challenge to deal with human population growth and at the same time making sure the water quality is good enough to go out and harvest.”

All bivalve shellfish filter water to feed on microalgae and breathe oxygen dissolved in the water, Barry said. But with algae also comes viruses and fecal coliform bacteria, which is a potential human health hazard.

The Central Puget Sound region — which runs from Vashon Island to Foulweather Bluff near Hansville — is divided into three subregions, based on tribal Usual and Accustomed areas. Suquamish alone harvests from Dyes Inlet through Agate Pass into Port Madison, including Liberty Bay. Suquamish shares this Kingston region with Tulalip.

Appletree Cove is still prohibited from harvesting any shellfish. The 162 acres was recently approved because of improved water quality data, said Mark Toy of the Office of Shellfish and Water Protection in the Department of Health.

The closure zone is now a 300-yard radius around the Kingston Sewage Treatment Plant outfall, which goes through the cove and is approximately 1 mile from the shoreline at a depth of 165 feet below mean-low water, according to Kitsap County.

Toy said the original wastewater plant was built in downtown Kingston in 1974. The new plant, a secondary treatment center, was built in 2005, located on 29 acres at the end of Norman Road.

The outfall area in and around Appletree Cove was not classified for commercial harvesting prior to 1997, and was then classified Prohibited in 1997. Toy’s department has tested the 162-acre area for improvements in pollution since 2008. The National Shellfish Sanitation Program reviewed the water quality samples, of which there were 30 taken in five years.

Commercial licenses are available to harvest in the newly approved area, but an organization or company has to be approved for a harvest site application, through the Department of Health.

Toy said the department is working to add 10,000 more acres of shellfish growing areas by 2020, according to the Puget Sound Action Plan.